This invention relates generally to a motor driven camera having a detachable drive unit which includes a motor drive circuit capable of being activated for driving a film wind-up and shutter charge motor upon receipt of an electrical signal representative of termination of a camera exposure.
One type of known motor driven camera having a detachable drive unit makes provision for transmission of a signal upon termination of an exposure to the drive unit for commencing the driving of a film wind-up and shutter charge motor thereof. Another type of such motor driven camera having a detachable drive unit makes provision for starting the drive of a film wind-up and shutter charge motor after a predetermined lapse of time from each shutter release without receiving any signal from the camera. The drive units used for such cameras of both types incorporate a release circuit triggered by a release member on the sides of the drive units so as to issue a shutter release signal which should be transmitted to the cameras from the drive units.
Therefore, the motor driven camera of the first-mentioned type requires at least two signal transmitting connections between the camera and the drive unit. In addition, if the camera is provided with a selector for effecting either a single frame photographing mode or a continuous photographing mode, a larger number of signal transmitting connections are required for transmitting the photographing modes selection signal to the release circuit and the drive unit. However, an increase in the number of signal transmitting connections results in a more complex camera construction and drive unit connecting mechanism, and requires accuracy in positioning the signal transmitting connections. Thus, it has been customary in cameras of the first-mentioned type to provide the selector on the side of the drive unit so that signal transmission of the photographing modes selection signal would not be necessary.
On the other hand, in the motor driven camera of the second-mentioned type, the shutter should always be controlled at shutter speeds which are shorter than the predetermined lapse of time during the continuous photographing mode because a film wind-up and shutter charge should not be carried out during exposure. This results in a restriction of the shutter speed setting, or renders automatic shutter speed control under dark scene brightness conditions impossible. In addition, if the camera is provided with a selector for effecting either a single frame photograhing mode or a continuous photographing mode, an additional signal transmitting connection is required for transmission of the photographic modes selection signal in the same manner and for the same reason as discussed for the camera of the first-mentioned type.